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readkey(3alleg4)


NAME

   readkey  - Returns the next character from the keyboard buffer. Allegro
   game programming library.

SYNOPSIS

   #include <allegro.h>

   int readkey();

DESCRIPTION

   Returns the next character from the keyboard buffer, in  ASCII  format.
   If the buffer is empty, it waits until a key is pressed. You can see if
   there are queued keypresses with keypressed().

   The low byte of the return value contains the ASCII code  of  the  key,
   and  the high byte the scancode. The scancode remains the same whatever
   the state of the shift, ctrl and alt keys,  while  the  ASCII  code  is
   affected  by  shift  and  ctrl  in  the normal way (shift changes case,
   ctrl+letter gives the position of that  letter  in  the  alphabet,  eg.
   ctrl+A  =  1,  ctrl+B  =  2,  etc).  Pressing  alt+key returns only the
   scancode, with a zero ASCII code in the low byte. For example:

      int val;
      ...
      val = readkey();
      if ((val & 0xff) == 'd')     /* by ASCII code */
         allegro_message("You pressed 'd'\n");

      if ((val >> 8) == KEY_SPACE) /* by scancode */
         allegro_message("You pressed Space\n");

      if ((val & 0xff) == 3)       /* ctrl+letter */
         allegro_message("You pressed Control+C\n");

      if (val == (KEY_X << 8))     /* alt+letter */
         allegro_message("You pressed Alt+X\n");

   This function cannot return character values greater than 255.  If  you
   need to read Unicode input, use ureadkey() instead.

SEE ALSO

   install_keyboard(3alleg4),    ureadkey(3alleg4),   keypressed(3alleg4),
   clear_keybuf(3alleg4), simulate_keypress(3alleg4)



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